Vent Free Logs: Smells and health concerns

Question regarding Vent Free Logs:

Smells, heat & respiratory concerns,

Q. My husband just had open heart surgery. We had a fireplace built 30 years ago and have been using a large buck stove. Because of his health conditions, we decided to go to Vent Free Natural Gas Logs. We have had a gas smell since we have had them installed.

The installer of our Vent free gas logs has been back and everything is correct. Today I called the gas company, no gas showed up on their monitor. But they could also smell the gas, “just a small odor”. I do not burn these thru the night, only from around 11: am to 8 or 9: pm and sometimes not that long. The biggest problem the gas odor is smelling stronger in two bedrooms 20 ft away. Nothing would show up on the gas company’s monitors, but they to could smell the odor.

First, they claimed it was our cold air return, but we do not use our furnace/heat and cut the logs off at night. Then they came up with when we took the buck stove out, there is a lot of creosote back in where the stove was which is now open and the logs are setting in. He is claiming the creosote is melting and causing the smell. Is this correct? Is there any product that I can get to clean this since it is baked on?

Stages of Creosote

Stage 1 Creosote is often a dusty looking or may appear as a coffee ground texture.


Stage 2 Creosote, This often starts out as a very layer of lightly glazed creosote in the chimney system. This creosote will expand rapidly as it catches fire and changes into a brittle, fragile and puffy styrofoam consistency and can then easily block the chimney flue cause serious smoking problems!


Stage 3 Creosote, this stinking, tar, or gummy substance can accumulate in the firebox, on the damper, in smoke-chamber or at the top of the chimney flue cap.


Creosote is a fuel and “could possibly ignite into a fire, and it does stink! Odors move as air moves in many homes. It is my experience that some air is “still moving”, even if the furnace is not running, or pushing or blowing the hot air out of the vents

Applying PCR using a slip casting method of coating the interior of the walls of the chimney flue system.

If any creosote is visible at the start of one of our repair or installation projects,  we would have included a price to remove all of this creosote from the firebox, smoke chamber and chimney flue with a product called Heat Shield PCR (Poultice Creosote Remover) manufactured by CeCure LLC; c/o Saver Systems

In most cases, this is not cheap to repair, but it does work and it will remove the creosote problem.

$1,200 to $1,900 dollars and possible higher are not uncommon. Once again PCR has resolved stinking flammable creosote problems for us.

We would have also included what is called a level 2 chimney cleaning inspection with our chimney scanning equipment. It is viewed as a “change of use” of fuel source according to the NFPA 2:11 or National Fire Protection Association. The standard for Chimney, Fireplaces, Vents and Solid fuel Burning Appliances.



I’m personally not a fan of vent-free logs at all. My customer’s odor problems alone and this is just one reason that I stopped selling Vent Free Gas units altogether.
Take some time to read your manufacturer’s installation instructions, as well as their printed CAUTIONS section.
To the best of my knowledge, most manufacturers will state something about opening a window while the vent-free products are in use, which seems somewhat defeating when you think of it.
Manufactures will also state how long of a period of time you can burn.

I also feel you may be using these logs way too long of a period of time. But again follow your Mfg. instruction or call their help or customer support line.

Always consider the health risks to your young ones.


I have often read heath cautions on the use of vent-free gas around seniors, small children as well as family members with respiratory problem warnings; to seniors, small children along with individuals with breathing problem would knock out about 85 % of families that I know of, from installing these log sets, including myself with my own bouts with asthma.

It has been stated that burning 100,000 BTU of natural gas in any form, generates about 1 gallon of water. So my question is, so where does that water go, especially since the chimney flue is now closed up tight. Another possible issue is the dramatic rise in temperature of surrounding masonry, wood mantel and any possible hidden. Construction framing on the sides or the fireplace or under the hearth.

I know well that many fireplace shops and chimney contractors sell lots of these vent free units to a homeowner on the warmth benefit. And many of their customers really love them. For me personally, I know well that vent free appliances’ actually do produce a huge amount of heat. But for me, it comes with a high cost, as well as potentially to many health and safety concerns to my customers, as well as my own family.

I hope that I have shed some additional insights, on possible solving your issue.


Clay Lamb

Clay Lamb is a Cincinnati Chimney Sweep contractor and the executive producer of the YouTube channel, podcast, and blog Ask the Chimney Sweep. He is also an award-winning educator and public speaker in the chimney and fireplace industry.….Educational Videos….American Chimney Cincinnati, OH We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites.

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